Sullen meaning : One who is solitary, or lives alone; a hermit. (chiefly in plural) Sullen feelings or manners; sulks; moroseness. Having a brooding ill temper; sulky. Gloomy; dismal; foreboding. Sluggish; slow. Lonely; solitary; desolate. Mischievous; malignant; unpropitious. Obstinate; intractable.